Introduction: Many people new to marketing think that Keyword Effectiveness Index (KEI) is the magic formula to achieve high ranking in the search engines and thereby secure a steady stream of money. The claim is supported by the documentation of almost all keyword research tools and has been repeated by thousands of inexperienced marketing people.

I say that if anyone says that the Keyword Effectiveness Index (KEI) is great to find good keywords/search terms, without explaining any of the drawbacks, then they are either out to cheat you or they just don’t know any better.

Definition: Keyword effectiveness index: A mathematical representation of the popularity of a keyword measured in number of searchers (demand), compared to its popularity measured as the number of pages in a search engines index (supply).

Description: KEI is a statistical formulation that reveals the most effective keyword phrases and terms to use in optimizing your web pages for. Efficiency can be many things. According to KEI, it is efficient to optimize for keywords that have many searchers, but only a few competing pages.

The lower the KEI, the more popular your keywords are, and the less competition they have. That means that you might have a better chance of getting to the top in the search engines and receive a good number of searchers for your effort.

Example: Suppose the number of searches for a keyword is 821 per day and Google displays 224,234 results (pages) for that keyword. Then the ratio between the popularity and competitiveness for that keyword is:

224,234 divided by 821. In this case, the KEI is 273.

Example on the opposite: Suppose the number of searches for a keyword is 2 per day and Google displays 11,224,234 results (pages) for that keyword. Then the ratio between the popularity and competitiveness for that keyword is:



Explanation: According to the KEI definition, the best keywords are those that have many searches and that don’t have much competition in the search results. A low KEI is therefore preferable.

In our example, it is clear that the keyword with a KEI of 273 sounds as a good keyword to optimized a pages for. It is just as clear, in the example on the opposite, that the keyword that has lots of competitors and a low number of searchers which gives a KEI equal to 5,612,117 is a tough fight for a small prices (unless the two searchers are very valuable;-).

However, the KEI makes no statement about the quality of the competition. While there might only be a few competitors in the search results, these competitors could be big players with big SEO teams and thousands of back links.

The number of search results can’t really tell you whether it is easy to get your web site listed in the top 10 results for that keyword or not. It’s much easier to move your web site from position 20,000 to position 12,000 than from position 190 to position 6.

In addition, the KEI factor is not a scientific number. It is more like a rule of thumb.
We will expect:

• The KEI for a keyword to increase if its popularity increases. Popularity is defined as the number of searchers.
• The KEI for a keyword to decrease if it becomes more competitive. Competitiveness is defined as the number of sites which a search engine e.g. Google displays when you search for that keyword using exact match.

As a general rule, it isn’t advisable to select or deselect keywords wholly on the basis of numbers like KEI.

Keyword statistic has some uncertainties attached. Keywords relevancy has to be the most important factor. Some of your keywords you are able to rank for in the search engines and other will give your users a good experience.

KEI Front page questionHistory: There haven’t been many successful metrics that have been calculated by two or more variables. The Keyword effectiveness index has been the most successful.

Future: There is a need for more useful variables in SEO and I predict there will come many in the future.

How to practice: When you have a keyword phrases, with a high, medium or low KEI, you need to be able to answer: Is there a reason why the KEI might be giving an incorrect picture?

There can be many reasons why KEI are showing you something you can’t use. Here are some of the reasons:

  1. The position of the words in the keyword phrases is unnatural.
    Ex. “keyword report” has 534,000 pages in Google’s index, and the more unnatural “report keyword” has 29,100 pages. This doesn’t mean there is 18 times less competitions for “report keyword”.
  2. More words in a keyword phrase means a much smaller changes to find them in a webpage.
  3. Search engines don’t give the accurate number of pages in their index.
  4. The number of searchers isn’t an accurate number and many times known keywords are inflated by the use of automated tools like webmastergold.

By blindly using KEI to select keywords, you run the risk to select keywords that have words in an unnatural order, long keyword phrases and known highly competitive keywords where it is mostly automated tool that search for them. Not good if you were looking for keyword phrases with little competition and many searchers.

Tips: Always ask yourself if there is a good reason why a keyword phrase has a low number, before you get all excited.

Some keyword phrases convert badly to customers and therefore it is easier to rank for them. Do you want to put a big effort to rank for low value keywords?

Links: Keyword, Keyword Demand, Keyword Phrase, Keywords vs. Search Terms.

Conclusion: Use Keyword Effectiveness Index (KEI) carefully. Is there any reason why KEI shows it is a good keyword to use, but it is not?

What is your experience with Keyword Effectiveness Index (KEI)?
Do you like to use Keyword Effectiveness Index (KEI)?
Do you have any alternative methods to find good keyword/search phrases?